Znamierowski 1999 shows several interesting flags of the Port Cities of northern Europe. These are derived from gonfanons, originally red in color. The flags, in a banner form [i.e. hanging flags], were flown from the stern of the vessels, the mast carrying the gonfanon of the colors. The oldest of the series that Znamierowski 1999 shows dates from the mid-13th century, that of Hamburg.